Recent reports have suggested that the diagnosis of neurofibromatosis can be made by finding giant pigment granules in dihydroxyphenylalanine-incubated epidermal whole mounts from café au lait spots. Our studies indicate that these "macromelanosomes" may not be found in the hyperpigmented macules in all cases of neurofibromatosis and that they may be less common in children. Failure to find such granules should not preclude a diagnosis of neurofibromatosis.
Silvers DN, Greenwood RS, Helwig EB. Café au Lait Spots Without Giant Pigment GranulesOccurrence in Suspected Neurofibromatosis. Arch Dermatol. 1974;110(1):87-88. doi:10.1001/archderm.1974.01630070055012